Valentine's Day Cards - since 1850s

History and Tradition (News story 2016) - Shelbyville Union Weekly Adversiser

The tradition of Valentine's Day cards did not become widespread in the United States, however, until the 1850s, when Esther A. Howland, a Mount Holyoke graduate and native of Worcester, Mass., began mass-producing them.  Today in the 21st Century, the holiday has become a booming commercial success.  According to the Greeting Card Association, 25 percent of all cards sent each year are valentines!